In control of operations of a machine or equipment, a method of using a minimum principle, a method of bang-bang control, and the like are used as methods for optimally performing the control.
Also, regarding a technique for optimally performing control, JP 2016-58561A discloses a component mounting apparatus for improving insufficient driving torque of a conveying belt. Also, JP 2009-81922A discloses a driving method for a pulse motor that increases the velocity of a pulse motor to a target velocity in a short amount of time while preventing step-loss.
JP 2016-58561A (published Apr. 21, 2016) and JP 2009-81922A (published Apr. 16, 2009) are examples of background art.
The above-described method of using the minimum principle and the method of bang-bang control are preferable if the conditions within the control segment are the same. However, if multiple steps with different conditions are included in the control segment, optimal control is not necessarily achieved. This will be described with reference to FIGS. 11 and 12. FIGS. 11 and 12 are diagrams for illustrating an example in which optimal control is not necessarily achieved with a conventional optimal control method in the case where multiple steps with different conditions are included in the control segment.
As shown in FIG. 11, a case of controlling an operation of moving reciprocally in a segment with a slope is considered. In this case, the slope is ascended during departure and the slope is descended during returning, and thus multiple steps with different conditions are included among all of the steps. With the conventional method, in order to optimally control such an operation, the driving time is designated for each step with a different condition, the optimal operation value in the driving time is derived, and the input locus for all steps is ultimately generated.
In other words, as shown in FIG. 12, processing in which, first, the driving time for step A is designated (S1201), the optimal operation value for the driving time is derived (S1202), and then, the driving time for step B is designated (S1203), the optimal operation value for the driving time is derived (S1204), . . . , is repeated for all steps, and the input locus for all steps is generated (S12XX).
When applied to the example shown in FIG. 11, the above-described processing is as follows. If 2 seconds is used as the overall driving time for the steps, there are two steps with different conditions, namely departing and returning, and therefore, first, the driving time for departing is designated as 1 second. Then, the optimal operation value for the driving time is derived. Here, for example, it is assumed that 30 Nm is the torque value. Next, the driving time for returning is designated as 1 second. Then, the optimal operation value for the driving time is derived. Here, for example, it is assumed that 20 Nm is the torque value. Since the return step is downhill, a value lower than that for departing is used.
In this case, the motor that controls all of the steps needs to be able to output a torque value of 30 Nm. However, since the optimal operation value in the returning step is 20 Nm, waste occurs in the motor. Accordingly, the optimal operation value cannot necessarily be derived in all of the steps.
One or more embodiments may been made in view of the foregoing problems, and may realize a control apparatus or the like that can perform optimal control in all steps.